Electric soldering iron



May 24, 1932. E. A. LOCKWOOD ELECTRIC SOLDERING IRON Filed Sept. 9. 1929 INVENTOR I W/iz/Z Z, 06/11 0062 ATTORNEY Patented May 24, 1932 UNITED STATES PATENT OFFICE ERWIN A. LOCKWOOD, OF ROYAL OAK, MICHIGAN, ASSIGNOR TO AMERICAN ELECTRICAL HEATER COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN ELECTRIC SOLDERING IRON Application filed September 9, 1929. Serial No. 391,495.

This invention relates generally to electrically heated tools such as soldering irons and constitutes an improvement upon the construction set forth in U. S. Letters Patent No. 1,270,303 dated June 25, 1918.

At the present time underwriters require that all electrical tools be grounded, therefore, I have modified the cable and terminal structure illustrated in the patent referred to above to comply with such requirements. In

the present instance this has been accomplished by (1) providing a flexible cable in which a ground wire is concealed with the two ordinary Wires, (2) providing a terminal structure in which the supporting bar extends farther into the insulating block and the latter is cut away to expose a portion of the bar, whereby the ground wire aforesaid may be connected thereto, and (3) providing a frusto-conical washer of insulating material upon the cable at one end of the insulating block so that the washer will hold the three wires of the cable in grooves in the block and will serve as a seat for the coil spring sleeved upon and protecting the cable.

In the accompanying drawings:

Figure 1 is an elevation of a tool embodying my invention;

Figure 2 is a view similar to Figure 1 but 3 showing the handle removed from the shank of the tool;

Figure 3 is a detail view of the insulator block;

Figure 4 is a top plan view of the construction shown in Figure 2.

Referring now to the drawings, 1 is a hollow shank of an electrically heated tool such as a soldering iron, 2 is a collar rigid with the shank at the rear end thereof, 3 is a flat metallic bar rigidly secured to and projecting rearwardly from the collar, and 4 and 5 respectively are electrical conductor plates riveted intermediate their ends to, but insulated from opposite sides of the bar 3. 6 and 7 are electrical conductors extending from the shank 1 and connected to the plates 4 and 5 at the forward ends thereof, 8 is an insulator block cast upon the bar 3 in rear of the plates 4 and 5 and having a transverse groove or channel 9 exposing a portion 10 of the bar,

and 11 is a flexible cable containing two ordinary wires 12 and 18 and a ground wire 14. As shown, the wires 12 and 13 are received in grooves 15 and 16 in the block 8 and are connected to the plates 4 and 5 at the rear ends thereof, while the ground wire 14 is received in a groove 17 in the block 8 and is connected by a set screw 18 to the exposed portion 10 of the bar. 20 is a handle threadedly engaging the collar 2 and concealing the bar 3, plates 4 and 5, block 8 and conductor terminals, 21 is a coil spring carried by the handle 20 and sleeved upon the cable 11 as a protector therefor, and 22 is a frusto-coni cal washer of insulating material on the cable at the rear end of the block holding the three wires 12, 13 and 14 in the grooves 15, 16 and 17 in the block 8 and serving as an abutment for the spring 21.

Thus with this construction the cable 11 contains all three wires, the block 8 receives the said wires and the screw 18 constituting the securing means for the ground wire, and the washer 22 holds the three wires in the grooves 15, 16 and 17 in the block and serves as a seat for the spring 21 when the parts are assembled. Thus the ground wire 14 is protected with the ordinary wires 12 and 13 from strains. The handle 20 may be readily engaged with or disengaged from the collar 2 on the shank and together with the spring 21 may be moved longitudinally of the cable so that the terminal connections are readily accessible.

What I claim as my invention is:

1. In an electrically heated tool, a shank, a terminal supporting bar projecting from the shank, electrical conductor plates carried by said bar, an insulator block upon said bar at one end of said plates and having a channel exposing a portion of the bar, and a cable having wires connected to the conductor plates and having a ground Wire connected to the exposed portion aforesaid of said bar.

2. In an electrically heated tool, a shank, a terminal supporting bar projecting from the shank, electrical terminals carried by said bar, an insulator block upon the bar adjacent to said terminals and having a channel exposing a portion of the bar,.a cable having wires extending over the insulator block and connected to the terminals and having a ground wire extending over the insulator block and connected to the exposed portion aforesaid of said bar, a handle concealing the bar, terminals and insulator block, a coil spring carried by the handle and sleeved upon the cable as a protector therefor, and a washer on the cable holding the Wires aforesaid in position relative to the insulator block and constituting a seat for the coil spring.

3. In an electrically heatel tool, a shank, a bar projecting from the shank, electrical terminals carried by the bar, an insulator block carried by said bar in rear of said terminals having a channel exposing a portion of said bar and having grooves therein, a cable hav ing wires in said grooves, two of said wires being connected to said terminals, the third wire being a ground Wire and connected to the exposed portion aforesaid of said bar,

and a washer carried by the cable adjacent the insulator block holding the wires aforesaid in the grooves in said block.

In testimony whereof I aifix my signature.

ERWIN A. LOCKWOOD. 

